bonding

• metallic bond

  the attraction between delocalised outer shell electrons and positive metal ions in a lattice
• ionic bonding

  the electrostatic attraction between oppositely charged ions in a lattice

  electrons transferred from metal to non-metal
• covalent bond

  a shared pair of electrons (between non-metals)
• co-ordinate bond

  a covalent bond in which both electrons of the shared pair come from the same atom
• electronegativity

  the power of an atom to attract the pair of electrons in a covalent bond
• van der Waals forces

  caused by the movement of electrons which unbalances the charge distribution within the molecule . this creates an instantaneous dipole across the molecule. the instantaneous dipole is constantly forming and dissappearing. this in turn induces a dipole in neighbouring molecules, resulting in weak forces of attraction between molecules. present between all molecules but they are the only forces between non-polar molecules.
• permanent dipole-dipole forces

  these occur between molecules which have a permanent dipole. they occur in addition to van der Waals forces. the $\delta+$ end of one molecule is attracted to the $\delta-$ end of a neighbouring molecule. usually stronger than van der Waals forces
• hydrogen bonding

  occurs between molecules which contain a hydrogen atom bonded to either F, O or N. a hydrogen bond iformed between a$\delta+$ H atom in one molecule and a lone pair of electrons on an N,O or F in a neighbouring molcule. they occur in addition to van der Waals forces. they are the strongest intermolecular force